An International Conference on Hydrogen Ion Transport in Epithelia has been organized as a special satellite symposium of the XXIX congress of the International Union of Physiological Sciences and will be held in conjunction with the Fall Meeting of the American Physiological Society in Honolulu, Hawaii, August 21-24, 1983. The purpose of the Conference is to provide a forum for scientists working on various aspects of hydrogen ion transport in artificial membranes, isolated cell membranes, simple non-epithelial cell systems and various epithelia. Presentations will be organized around the following general topics. I. Theoretical and experimental work on hydrogen ion diffusion in lipid bilayers, cell membranes, surface barriers and paracellular pathways. II. Hydrogen Ion pumps in simple non-epithelial cell systems (bacterial rhodopsin, chloroplasts, mitochondria) and isolated membrane vesicles. III. Electrophysiologic analysis of hydrogen ion transport in various epithelia (stomach, intestine, gall bladder, pancreas, salivary glands, kidney and urinary tract). IV. Structure-function relations, regulatory processes and metabolic coupling of hydrogen ion transport in isolated cells or glands and intact epithelia.